Intermetallic compounds

ABSTRACT

Intermetallic compounds and hydrides thereof, characterized in that they have been prepared by reacting hydrides of the elements of the main groups I, II, III and IV of the Periodic Table, magnesium hydridehalides or magnesium dialkyls having the general formula MgR 2  (R=alkyl) in a solvent with bisallyl metal compounds of the metals of the subgroup VIII of the Periodic Table or of zinc or with the homologues of the bisallyl compounds of said metals, and processes for preparing said compounds.

This is a division of application Ser. No. 547,403, filed Jul. 2, 1990now U.S. Pat. No. 5,133,920 which is a continuation of Ser. No. 304,994,filed Feb. 1, 1989, now abandoned, which is a division of Ser. No.39,495, filed Apr. 16, 1987, now U.S. Pat. No. 4,828,606.

The present invention relates to a process for preparing intermetalliccompounds or the hydrides thereof by means of a non-metallurgical, i.e.wet-chemical, route under extremely mild conditions (e.g. roomtemperature, normal pressure), whereby the products are obtained in afinely distributed, highly active predominantly amorphous state.

Intermetallic compounds and the hydrides thereof have gained increasingtechnical importance during the recent 10 to 15 years.

According to prior art, such intermetallic compounds or metal alloys areprepared from two or more components by a melt process at a hightemperature (cf. H. Buchner, "Energiespeicherung in Metyllhydriden",Springer Verlag 1982, page 65).

Furthermore, evaporation techniques of metals such as, e.g., thepreparation of the supra-conducting Nb₃ Si (E. Amberger, U. Siefken, J.Less-Common Metals 75, (1980) 273) have become known.

Inter-metal compounds of metals of the main groups V and VI of thePeriodic Table, on the one hand, with metals of the groups II to IV, onthe other hand, such as GaAs., CdSe, SnSe which--such as, e.g.,GaAs--are used in semiconductor technology, can be prepared by a"non-metallurigcal route" by the reaction of organometal compounds ofthe respective metals [Ga(CH₃)₃), Al(CH₃)₃)] with element hydrides (PH₃,AsH₃) in the gaseous state at high temperatures (of from 500° C. to 700°C.). The method has gained technical relevance for the preparation ofsemiconductor material (P. D. Dapkus, "Metalorganic chemical vapordeposition", Annual Review Material Sciences 12 (1982) 243].

L. H. Dubois and R. G. Nuzzo (U.S. Pat. No. 4,507,401) claim a processfor preparing intermetallic compounds used as catalysts fordehydrogenations of alkanes, which process is characterized in thatmetals, such as, e.g., finely distributed metallic nickel, fixed toinorganic carriers are reacted with gaseous organometal compounds ormetal hydrides, such as, e.g., hexamethyldisilane or Si₂ H₆, at elevatedtemperature (e.g. 300° C.). Evidence of the formation of intermetalliccompounds, e.g. of nickel silicides in the reaction of Ni with Si₂ H₆,has not been furnished.

Intermetallic compounds in amorphous form ("metallic glasses") arecommercially produced by quenching melts, in which processes extremelyhigh cooling rates (10⁶ ° C./s) are necessary to eliminate any formationof crystallization seeds, which involves high technical expenditure (P.Duwez, Progr. Solid State Chem. 3 (1966) 377]. In addition,intermetallic compounds in an amorphous state may be obtained by thecondensation of metal vapors [W. Buckel, R. Hilsch, Z. Physik 138 (1954)109] or by the diffusion of the metals at temperatures below thecrystallization temperature [Au_(1-x) La_(x) (0,3≦x≦0,5), R. B. Schwarz,W. L. Johnson, Phys. Rev. Lett. 51 (1983) 415].

Ternary hydrides (hydrides of intermetallic binary compounds) have beenknown to be prepared by subjecting intermetallic compounds, after aso-called activation process (comminution, full heating under aprotective gas), to a series of from 5 to 15hydrogenation-dehydrogenation cycles until the optimum hydrogenationrate and load will have been reached.

Further methods of the preparation of hydrides of intermetalliccompounds comprise the reaction of metal hydrides with metals in thepresence of hydrogen at high temperatures [e.g. Eu₂ RuH₆, J. S. Thompsonet al., Inorg. Chem. 14 (1975) 1866; Yb₂ RhH₆, R. Lindsay et al., Inorg.Chem. 15 (1976) 3050] or the reaction of two metals in a finelydistributed state with hydrogen at high temperatures [Mg₂ FeK₆, J.-J.Didisheim et al., Inorg. Chem. 23 (1984) 1953; Mg₂ CoH₅, P. Zolliker etal., Inorg. Chem. 24 (1985) 4177].

Intermetallic hydrides in an amorphous state are obtainable by thehydrogenation of crystalline intermetallic compounds at a temperaturebelow the crystallization temperature of the hydrides [hydrogenation ofLaNi₂, LaNi₃ and La₂ Ni₇ : H. Oesterreicher, J. Clinton, H. Bittner,Nat. Res. Bull. 11 (1976) 1241; hydrogenation of Zr₃ Rh: K. Samwer, X.L. Yeh, W. H. Johnson, J. Non-Crystalline Solids 61, 62 (1984) 631].

It has now surprisingly been found that intermetallic compounds or thehydrides thereof may be readily formed from the hydrides of the elementsof the main groups I to IV of the Periodic Table (M¹ H_(n) component),e.g. HMgCl, or magnesium dialkyls in an organic solvent at a temperatureof from -100° C. to 100° C.--and preferably at from 0° C. to +50° C.--bythe reaction with bisallyl metal compounds of the metals Ni, Pd, Pt orZn [M² (C₃ H₅)₂ component), for example, allyl or homologues thereofsuch as methallyl, e.g. bis(³ -methallyl) nickel or -palladium. Assuitable metal hydrides there are preferred to be employed magnesiumhydride (European Patent No. 0 003 564) and lithium hydride (U.S. Pat.No. 4,396,589). Characteristic for the reaction according to theinvention is the partial or complete removal of the allyl group of theM² (C₃ H₅)₂ component in the form of propane (equations 1 to 4hereinbelow) and the precipitation of the intermetallic compounds or ofthe hydrides thereof in an amorphous state.

Accordingly, the present invention relates to intermetallic compoundsand the hydrides thereof which are characterized by that they have beenprepared by reacting hydrides of the elements of the main groups I, II,III and IV of the Periodic Table, magnesium hydridehalides or magnesiumdialkyls having the general formula MgR₂ (R=alkyl) in a solvent withbisallyl metal compounds of the metals of the subgroup VIII of thePeriodic Table or of zinc, the bisallyl compound including allyl andhomologues thereof.

The invention further relates to a process for the preparation ofintermetallic compounds and of the hydrides thereof, which process ischaracterized in that hydrides of elements of the main groups I, II, IIIand IV of the Periodic Table, magnesium hydridehalides or magnesiumdialkyls having the general formula MgR₂ (R=alkyl) are reacted in asolvent with bisallyl metal compounds of the metals of the subgroup VIIIof the Periodic Table or of zinc.

The hydrides of the elements of the main groups I and II of the PeriodicTable are preferred in the present invention.

The elements of the groups I to IV of the Periodic Table may beexemplified by lithium, sodium, potassium, beryllium, magnesium,calcium, strontium, barium, boron, and silicon. Among these, lithium,magnesium, calcium, barium, boron and silicon are preferred. Magnesiumis most preferred.

As the magnesium hydridehalide there may be used magnesiumchloridehydride and magnesium bromidehydride, magnesium chloridehydridebeing preferred.

In the general formula MgR₂ of the magnesium dialkyls, the alkylmoieties R preferably have from 1 to 8 carbon atoms.

As metals of the subgroup VIII of the Periodic Table there may bementioned preferably nickel, palladium or platinum. However, the othermetals of the subgroup VIII of the Periodic Table, viz, iron, cobalt,nickel, ruthenium, rhodium, osmium and iridium may be employed as well.

The solvents to be employed in the present invention may be any solventswhich are inert to the reactants. Preferred solvents aretetrahydrofuran, toluene and ether.

The reaction may be carried out at conventional temperatures within therange of from -100° C. to +100° C., and preferably of from 0° C. to +50°C.

As examples of intermetallic compounds and of the hydrides thereofaccording to the present invention there may be mentioned the following:

Intermetallic compound MgPd in the amorphous state;

Intermetallic compound MgNi in the amorphous and in the crystallinestates;

Crystalline, intermetallic compound Mg₂ Pd and its hydride Mg₂ PdH₂ inthe amorphous and in the crystalline states;

Intermetallic compound Mg₂ Pt and its hydride Mg₂ PtH₂ ;

Intermetallic compound MgPt;

Intermetallic compounds Li₂ Ni and LiNi;

Intermetallic compounds BaNi and Ba₂ Ni;

Intermetallic compound LiPd in the amorphous state;

Intermetallic compound Li₂ Pt in the amorphous state; and

Intermetallic compound Ca₂ Pd and its hydride.

The formation of the intermetallic compounds (equations 1, 1a, 3a and 4)and of the hydrides thereof (equations 2, 3) in the process according tothe invention may be illustrated by the following reaction equations:

    ______________________________________                                         ##STR1##                     (1)                                             M.sup.1  n            M.sup.2                                                                             Example                                           ______________________________________                                        Mg       2            Ni     3                                                Mg       2            Pd     7                                                Mg       2            Pt     9                                                Ba       2            Ni    13                                                Li       1            Ni    14                                                Li       1            Pt    17                                                ______________________________________                                         ##STR2##                     (1a)                                             ##STR3##                     (2)                                             M.sup.1        M.sup.2                                                                             Example                                                  ______________________________________                                        Mg             Ni    1                                                        Mg             Pd    6                                                        Mg             Pt    8                                                        Ca             Pd    11                                                       Ba             Ni    12                                                       ______________________________________                                         ##STR4##                     (3)                                              ##STR5##                     (3a)                                             ##STR6##                     (4)                                             ______________________________________                                    

The process according to the present invention allows an easypreparation of intermetallic compounds so far unknown as well as ofpreviously known intermetallic compounds or previously known ternaryhydrides in an amorphous and particularly reactive state and also in thecrystalline state. The intermetallic compounds or hydrides thereof asprimarily obtained in an amorphous state according to the equations 1 to4 may be rid of contaminations (organic components) by repeatedhydrogenation-dehydrogenation cycles.

Upon variation of the molar ratio of the two reactants M¹ H_(n) and M²(C₃ H₅)₂ there will be obtained various intermetallic compounds orhydrides thereof, some of which are so far unknown, as will be furtherillustrated by way of Examples.

In the Mg-Ni phase diagram there have so far been known twointermetallic phases, Mg₂ Ni and MgNi₂, which are obtainable by meltprocesses. The intermetallic compound Mg₂ Ni may be reversiblyhydrogenated to form the intermetallic compound Mg₂ NiH₄ which is one ofthe best known high-temperature hydrogen storage systems; contrarythereto, the intermetallic compound MgNi₂ is not capable of beinghydrogenated [J. J. Reilly, R. H. Wiswall, Inorg. Chem. 7 (1968) 2254].

In the reaction of catalytically prepared magnesium hydride with bis(n³-allyl)nickel in a molar ratio of 2:1 the present process yields anamorphous hydride of the approximate composition Mg₂ NiH₂.

In contrast to the metallurgically prepared Mg₂ Ni, the product preparedaccording to the invention (specific surface area 20 m² /g) may bereversibly hydrogenated already under normal pressure at 200° C. to formMg₂ NiH₄.

If, however, catalytically prepared magnesium hydride is reacted withbis(η³ -allyl)nickel in a molar ratio of 1:1 (equation 1) or solublemagnesium chloridehydride is reacted with bis(η³ -allyl)nickel in amolar ratio of 2:1 (equation 1a), then in both cases an amorphous solidis obtained which has been proven to be a so far unknown intermetalliccompound having the composition of MgNi. MgNi cannot be hydrogenatedunder standard conditions. MgNi is a metastable compound which is notaccessible via the metallurgical route. Only upon continued annealing at730° C. MgNi is slowly and incompletely converted into the knownthermodynamically stable Mg₂ Ni.

In the reaction of catalytically prepared magnesium hydride with bis(η³-allyl)palladium or bis(η³ -methallyl)palladium in a molar ratio of 2:1there is formed a so far unknown amorphous hydride Mg₂ PdH which upondehydrogenation and a hydrogenation/dehydrogenation cycle is convertedinto a previously unknown crystalline intermetallic compound Mg₂ Pd.

Active magnesium hydride reacts with bis(η³ -allyl)palladium accordingto equation 1 in a molar ratio of 1:1 to form the amorphousintermetallic compound mgPd which may also be obtained from magnesiumdiethyl and bis(η³ -allyl)palladium in a molar ratio of 2:1 (equation4). An intermetallic compound MgPd in an amorphous state has so far notbeen known, in contrast to the known crystalline cubic MgPd (CsCl type)[S. N. Sharma, A. Weiss, J. Less-Common Metals 104 (1984) 45] and theknown crystalline tetragonal Pd₁.1 Mg₀.9 (AuCu type) [L. Westin, ActaChem, Scand. 22 (1968) 2574].

Catalytically prepared magnesium hydride reacts with bis(η³-allyl)platinum in a molar ratio of 2:1 to form the amorphous ternaryhydride Mg₂ PtH₂ (equation 2) and in a molar ratio of 1:1 to form theintermetallic compound MgPt (equation 1).

Active lithium hydride (U.S. Pat. No. 4,396,589) reacts with bis(η³-allyl)nickel in a molar ratio of 2:1 to form the amorphous Li₂ Ni(equation 1) and in a molar ratio of 1:1 to form amorphous LiNi.

In the system nickel-lithium so far no intermetallic phases have beendetermined [Y. Takeuchi et al., Metallwissenschaft und Technik 20,January 1966, 2]. Thus, for example, nickel is capable of dissolvingonly 0.4% of lithium at 1200° C., while a lithium melt at the nametemperature is capable of dissolving only 3.5% of nickel. The processaccording to the invention makes it possible to prepare amorphouslithium-nickel intermetallic compounds.

Barium hydride reacts with bis(η³ -allyl)nickel in a molar ratio of 2:1to form the amorphous ternary hydride Ba₂ NiH₂ (equation 2) and in amolar ratio of 1:1 to form the previously unknown amorphousintermetallic compound BaNi (equation 1).

In the system nickel-barium [Y. Takeuchi et al.] so far no intermetallicphases have been determined. The two alloy components are only partiallymiscible in the liquid state and form a miscibility gap in a wideconcentration range. In accordance with the process of the invention ithas now become possible to prepare amorphous nickel-barium intermetalliccompounds and ternary hydrides, respectively.

The present process further enables preparing the known or unknowncompounds set forth hereinbelow and/or hydrides thereof, respectively,in addition to the aforementioned compounds.

Active magnesium hydride reacts with bis(allyl) zinc in a molar ratio of1:1 to form the so far unknown amorphous hydride MgZn₂ H₂ (equation 3).

Catalytically prepared lithium hydride reacts with bis(η³-allyl)palladium in a molar ratio of 2:1 (equation 3a) to form anamorphous intermetallic compound having the composition Li_(1:5) Pd.

In the reaction of active lithium hydride with bis(η³ -allyl)platinum ina molar ratio of 2:1 (equation 1) there is formed an amorphousintermetallic compound having the composition Li₂ Pt which is capable ofbeing reversibly hydrogenated under standard conditions.

The reaction of calcium hydride with bis(η³ -allyl)palladium in a molarratio of 2:1 (equation 2) results in the hydrogenation of the Palladiumpresent in the product mixture.

In summary, the following advantages over the state of the art of thepresent process for preparing intermetallic compounds and/or therespective hydrides may be mentioned:

1. The preparation is carried out via a wet-chemical route underextremely mild conditions (e.g. room temperature) and, thus, enables thepreparation of compounds of this type to be effected which are notobtainable via a metallurgical route as they do not exist at hightemperatures (being metastable). Those new intermetallic compounds, onceprepared at a low temperature, such as, for example, MgNi, may prove tobe of a surprising thermal stability.

2. By varying the molar ratio of the starting components M¹ H_(n) and M²(C₃ H₅)₂ in the synthesis, various defined intermetallic compounds orthe hydrides thereof aimed at may be prepared.

3. Due to the mile reaction conditions, the intermetallic compounds orthe hydrides thereof are obtained in an extremely finely distributedhighly reactive form, i.e. such having a large specific surface area.This gives rise, on the one hand, to superior kinetics ofhydrogenation-dehydrogenation as compared to that of the metallurgicallyprepared intermetallic compounds and, on the other hand, to an increasedcatalytic activity of said compounds.

Intermetallic compounds and/or the hydrides thereof obtained accordingto the present process are mostly amorphous, i.e. in the form ofmetallic glasses, since they have been produced at temperatures belowthe crystallization temperature.

Thus, the process is a novel process for preparing amorphous metallicmaterials and the hydrides thereof wherein the conventional techniquesof extreme quenching are dispensable. As a rule, said compounds may beconverted into crystalline intermetallic compounds by heating orannealing at temperatures above the crystallization temperature.

The intermetallic compounds or hydrides thereof preparable according tothe process of the present invention may be used, inter alia, asreversible hydrogen storage systems, as catalysts, as regeneratablehydrogen donors and acceptors for chemical processed and further forhydrogen separation and purification.

Among the physicochemical properties of certain intermetallic compoundsand alloys of particular technical interest is the superconductivitybelow relatively high superconductive transition temperatures T_(c)(transition from the metallic state to the superconductive). The highestsuperconductive transition temperature of all superconductors so farknown is that of Nb₃ Ga amounting to 23.2 K. Superconductingintermetallic compounds such as, e.g., Nb₃ Sn, are technically used assuperconducting materials in cryomagnets for producing extremely highmagnetic fields (>2 Tesla).

A further application in the field of intermetallic compounds is the"metallic glasses", i.e. the intermetallic compounds or alloys in anamorphous state. Technical applications of magnetic glasses, due totheir magnetic properties, are contemplated to exist in transformertechnology (energy saving in power transformation due to use of metallicglasses as transformer cores) and in application as metallic materialshaving a particularly high mechanical strength and/or corrosionresistance. Metallic glasses are also of interest with view to theproperties thereof as superconductors and as catalysts.

The invention will be further described in the following Examples inconjunction with the accompanying drawing, wherein

FIG. 1 is a plot of the hydrogen consumption rate against the reactiontime for various nickel catalysts.

All operations described in the following Examples are carried out underargon.

EXAMPLE 1

6.81 g of MgH₂ (223 mmol) (composition: Mg 84.7, H 7.0, C 4.6, Cl 2.6,Cr 0.4%; 86 per cent after thermolysis) [European Patent No. 0 003 564]were suspended in 200 ml of tetrahydrofuran (THF) and were admixed in aclosed system with a solution of 15.76 g (112 mmol) of Ni(η³ --C₃ H₅)₂in 50 ml of THF. The suspension was stirred at room temperature (RT),whereupon the initial yellow-orange color of the suspension changed toblack within 0.5 h. After 36 h the Ni concentration in the solutionremained constant at 0.07 mmol of Ni/ml; after 96 h, Ni(η³ --C₃ H₅)₂ wasno longer detectable in the solution. The batch was stirred at RT for 96h altogether; then the volatile components were evaporated at RT and0.27 mbar (0.2 mmHg) and condensed in two cold traps arranged in series(-78° and -196° C. ). The gases condensed in the trap cooled at -196° C.were evaporated, collected in a gas burette and analyzed by massspectroscopy; the condensate of the trap cooled at -78° C. was analyzedfor diallyl and residual gases by gas chromatography. Thus, of the C₃ M₅groups employed as Ni(η³ --C₃ H₅)₂, 76% were detected in the form ofpropane and 3% were detected in the form of propane. The solid residuewas stirred with fresh THF (500 ml) for 24 h, the black solid wasseparated from the solution by filtration, washed with THF untilcolorless and then with pentane and thereafter dried at RT under highvacuum.

Obtained were 13.70 g of a black, highly pyrophoric powder having thecomposition Mg 15.9, Ni 40.3, H 3.9, C 15.2, Cl 0.4, and Cr 0.04% (83%of the theory, relative to Ni), conforming to an empirical formula ofMg₂.15 Ni₁.00 H₅.68 C₁.83 Cl₀.02 and having a specific surface area of98 m² /g (BET method). According to the X-ray powder analysis, the solidwas amorphous, except for very weak lines of MgH₂.

In a fully automatically operated, electronically controlled apparatus11.30 g of the above powder were first heated to 400° C. and subjectedto a series of 34 hydrogenation/dehydrogenation cycles.

Upon rapid heating (about 40° C./min), an exothermic gas evolution beganat 120° C. (internal temperature of the sample) in the course of whichthe sample was heated to 300° C. for a short time, and 1200 ml of gas(20° C., 1 bar) having the composition H₂ 65%, CH₄ 5%, C₃ H₈ 8%, n--C₄H₁₀ 11%, n--C₄ H₈ 5% were released. From 270° C. to 335° C. (internaltemperature of the sample) there was an endothermic evolution of gaswithin 15 min whereby 1380 ml of gas (20° C., 1 bar) having thecomposition H₂ 71%, CH₄ 17%, C₃ H₈ 2%, n--C₄ H₈ 8% were evolved. In thesubsequent hydrogenation/dehydrogenation cycles the samples with respectto kinetics showed a behaviour comparable to that of a sample ofmetallurgically prepared Mg₂ Ni [J. J. Reilly, R. H. Wiswall, Inorg.Chem, 7 (1968) 2254]. After the first 5 cycles (hydrogenation: 334° C.,15 bar, 1.5 h; dehydrogenation: 334° C., normal pressure, 1.5 h), the H₂capacity of the sample in the residual 29 cycles (hydrogenation: 200° C.and 260° C., 1, 3, 5 and 10 bar, 1 h; dehydrogenation: 334° C., normalpressure, 1.5 h) remained constant at 2.65% by weight (calc. for Mg₂NiH₄ 3.62% by weight). In contrast to the metallurgical Mg₂ Ni sample,the Mg₂ Ni thus prepared was capable of being hydrogenated under normalpressure at 200° C., while in its X-ray powder diagram it was identicalwith the metallurgical Mg₂ Ni sample.

After another hydrogenation, there was obtained a carbon free Mg₂ NiH₄(composition: Mg 42.9, Ni 48.6, H 2.64, Cl 1.6, and Cr 0.2%) which wasidentified as such by X-ray powder analysis [Z. Gavra et al., Inorg.Chem. 18 (1979) 3595].

EXAMPLES 2 TO 10

The experiments in Examples 2 to 10 were carried out analogously toExample 1. The starting materials, reaction conditions and experimentalresults are summarized in Tables 1 and 1a.

                                      TABLE 1                                     __________________________________________________________________________    Reactions of catalytically prepared magnesium hydride with                    bis(allyl)metal compounds (M.sup.2 A.sub.2)                                   at room temperature to give intermetallic compounds or ternary hydrides.      Ex-                Sol-                                                                              React.-       Comp.: Elem. Analysis [%]                ample                                                                             MgH.sub.2 .sup.a)                                                                    M.sup.2 A.sub.2                                                                       vent                                                                              Time                                                                              Propene.sup.b)                                                                      Solid                                                                             Mg M H C Cl    Yield.sup.c)              No. g (mmol)                                                                             g (mmol)                                                                              [ml]                                                                              [h] [%]   [g] Empirical Formula                                                                            [%] RP.sup.d)             __________________________________________________________________________    2   1.02 (33.7)                                                                          Ni(meth.-A).sub.2 .sup.e)                                                             THF 192.sup.f)                                                                        79.4  1.25                                                                              44.3 35.0 4.0 9.5                                                                            44  amorphous                        2.60 (16.8)                                                                           (35)    (0.6)     Mg.sub.3.05 Ni.sub.1.00 H.sub.8.02                                            C.sub.1.33                               3   1.18 (35.2)                                                                          NiA.sub.2                                                                             THF 116.sup.g)                                                                        68    3.39                                                                              22.7 54.3 3.2 17.1                                                                           89  amorphous                        (35.2)  (50)    (2)       Mg.sub.1.00 Ni.sub.1.00 H.sub.3.41                                            C.sub.1.52                               4   4.83 (80.0).sup.h)                                                                   NiA.sub.2                                                                             THF 48  73    2.02                                                                              20.5 51.5 2.0 13.2                                                                           445 amorphous                        (40.0)  (123)   (3)       Mg.sub. 0.96 Ni.sub.1.00 H.sub.4.33                                           C.sub.1.25 Cl.sub.0.25                   5   1.33 (43.3)                                                                          PdA.sub.2                                                                             THF 17.sup.i)                                                                         96    3.50                                                                              28.3 66.6 1.66 3.2                                                                           99  amorphous                        4.04 (21.5)                                                                           (55)              Mg.sub.1.86 Pd.sub.1.00 H.sub.2.63                                            C.sub.0.43                               6   0.79 (23.5)                                                                          Pd(meth.-A).sub.2 .sup.j)                                                             Tol.                                                                              96.sup.k)                                                                         78    2.08                                                                              28.5 62.2 2.18 6.9                                                                           99                                   2.63 (12.1)                                                                           (40)    (4)       Mg.sub.2.01 Pd.sub.1.00 H.sub.3.7                                             C.sub.1.00                               7   0.55 (17.8)                                                                          PdA.sub.2                                                                             THF 24.sup.i)                                                                         93    2.38                                                                              16.5 73.2 1.31 4.4                                                                           95  amorphous                        3.26 (17.3)                                                                           (65)              Mg.sub.0.98 Pd.sub.1.00 H.sub.1.89                                            C.sub.0.53                               8   1.14 (37.0)                                                                          PtA.sub.2                                                                             THF 20.sup.i)                                                                         95    4.43                                                                              18.7 74.7 0.97 4.3                                                                           96  amorphous                        4.91 (17.7)                                                                           (76)    (7)       Mg.sub.2.00 Pt.sub.1.00 H.sub.2.51                                            C.sub.0.93                               9   0.45 (14.6)                                                                          PtA.sub.2                                                                             THF 24.sup.i)                                                                         81    2.87                                                                              10.7 84.8 0.65 3.74                                                                          86  amorphous                        4.04 (14.6)                                                                           (45)    (7)       Mg.sub.1.02 Pt.sub.1.00 H.sub.1.48                                            C.sub.0.72                               10  0.71 (23.1)                                                                          ZnA.sub.2                                                                             THF 20  46    1.55.sup.1)                                                                       14.6 79.1 0.89 0.98                                                                          82  Zn                               3.37 (22.9)                                                                           (60)    (2)       Mg.sub.1.00 Zn.sub.2.00 H.sub. 1.47                                           C.sub.0.14                               __________________________________________________________________________     .sup.a) MgH.sub.2 85%, prepared.                                              .sup.b) The figures in brackets denote % of propane.                          .sup.c) Relative to initially employed M.                                     .sup.d) X-ray powder analysis.                                                .sup.e) Bis(η.sup.3 -methallyl)nickel.                                    .sup.f) 53% of bis(η.sup.3 -methallyl)nickel unreacted after 48 h;        after 8 d only traces pf bis(η.sup.3 -methallyl)nickel detected in th     solution.                                                                     .sup.g) C.sub.3 H.sub.6 : 60% of theory after 48 h; after further 88 h        bis(η.sup.3 -allyl)nickel no longer detectable in solution.               .sup.h) HMgCl used in the place of MgH.sub.2.                                 .sup.i) After this time any bis(η.sup.3 -allyl)metal compound no          longer detectable in solution.                                                .sup.j) Bis(η.sup.3 -methallyl)palladium.                                 .sup.k) Followed by heating at 70° C. for another 24 h.                .sup.l) 13 mmol of bis(allyl)magnesium were determined in the reaction        solution (IR and .sup.1 HNMR spectra; protolysis).                       

                                      TABLE 1a                                    __________________________________________________________________________    Dehydrogenation of the ternary metal hydrides and thermal treatment of        the intermetallic compounds,                                                  respectively, of the Examples 2 to 10 and results of X-ray powder             analyses.                                                                     Ex- 1st Dehydr. or Therm. Treatm..sup.a)                                                                   2nd Dehydr. or Therm. Treatm..sup.a,e)                                                         Composition [%].sup.f)          ample                                                                             ml of Gas.sup.b) Comp. of Gases [%].sup.c)                                                             ml of Gas.sup.b) Comp. of Gases                                                                Mg M H Cc)                      No. Amount [g]                                                                          H.sub.2                                                                         CH.sub.4                                                                         C.sub.2 H.sub.6                                                                  C.sub.3 H.sub.8                                                                  C.sub.4 H.sub.10                                                                 .sup.d)                                                                            Amount [g]                                                                           H.sub.2                                                                            CH.sub.4                                                                           Empirical                                                                                RP.sup.g)            __________________________________________________________________________    2   321   90                                                                               7       4  Mg.sub.2 Ni.sup.h)                                                            (Mg)                                                  3   136   14                                                                              67 1  7  4  amor-                                                                              60     78   22   27.5 65.0 1.25 6.1                                      phous                 Mg.sub.1.00 Ni.sub.1.00                                                       H.sub.1.12 C.sub.0.46           4   114   39                                                                              43 -- 9  10 MgNi.sub.3 C.sub.x                                    5   155   93                                                                               2 -- 3  2  j)   108.sup.k)                                                                           100  --              Mg.sub.2 Pd          6   137   89                                                                               7 -- 3  2        96.sup.k)                                                                           98    2   28.4 68.4 0.56                                                                           Mg.sub.2 Pd                                                        Mg.sub.1.80 Pd.sub.1.00                                                       H.sub.0.86 C.sub.0.30           7    31   47                                                                              35 2  6  9       0                17.3 74.6 0.28                                                                           amorphous                                                          Mg.sub.1.00 Pd.sub.1.00                                                       H.sub.0.39 C.sub.0.17           8    87   80                                                                               3 1  9  8       0                20.1 78.5 0.50                                                                           amorphous                                                          Mg.sub.2.06 Pt.sub.1.00                                                       H.sub.1.23 C.sub.0.10           9    34   13                                                                              47 5  25 7       0                11.8 86.9 0.28                                                                           amorphous                                                          Mg.sub.1.10 Pt.sub.1.00                                                       H.sub.0.62 C.sub.0.17           10  144   96                                                                              -- -- 4  --       0.sup.1)                   MgZn.sub.2           __________________________________________________________________________     .sup.a) A sample of 1 to 2 g of the solid is heated in the                    thermovolumetric apparatus [B. Bogdanovic, B. Spliethoff, Chem. Ing.          Techn. 55 (1983) 156] from room temperature to 400° C. at a heatin     rate of 1° C./min.                                                     .sup.b) 20° C., 1 bar.                                                 .sup.c) According to massspectrometrical analysis.                            .sup.d) Result of Xray powder analysis after the 1st dehydrogenation or       thermal treatment, respectively.                                              .sup.e) After the sample had been hydrogenated in an autoclave at 15 bar      and 210° C. for 24 h.                                                  .sup.f) After the 2nd dehydrogenation or thermal treatment, respectively,     according to elementary analysis.                                             .sup.g) Result of Xray powder analysis after the 2nd dehydrogenation or       thermal treatment, respectively.                                              .sup.h) The sample still contains 1.2% of C and 0.9% of H.                    .sup.i) E. Scheid et al Z. Metallk. 44, (1953) 387                            .sup.j) The sample shows low crystallinity. Elementary analysis: Mg 30.8,     Pd 67.5, H 0.55, C 1.1%; empirical formula Mg.sub.2.00 Pd.sub.1.00            H.sub.0.86 C.sub.0.14                                                         .sup.k) A dehydrogenation taking place at a maximum speed in a narrow         temperature range is observed at 250-255° C.                           .sup.l) After the hydrogenation (10 bar, 100° C., 24 h) the sample     did not evolve any gas upon heating up to 300° C.                 

EXAMPLE 4

In the Example, instead of MgH₂ there was employed the THF-soluble HMgCl(European Patent 0 003 564) with bis(n³ -allyl)nickel in a molar ratioof 2:1. The specific surface area of the crude product was 112 m² /gafter drying under high vacuum and 2.2 m² /g after the thermal treatment(Table 1a). In the thermal treatment (heating up to 400° C.) theamorphous product is converted into a crystalline product at 290° C. TheX-ray powder diagram after the thermal treatment shows broad reflectionsof MgNi₃ C_(x). The sample was annealed at 660° C. for 1 h, whereuponthe reflections became sharp in appearance.

    ______________________________________                                        d[A].sub.exp.                                                                           d.sub.calc.  hxl    I.sub.exp.                                      ______________________________________                                        4.102                         7.1                                             3.824     3.817        001    17.3                                            2.204     2.203        101    100.0                                           2.108                         11.0                                            1.908     1.909        002    57.7                                            1.708     1.706        111    5.7                                             1.490                         6.9                                             1.349     1.349        112    28.7                                            1.151     1.151        103    22.0                                            1.102     1.102        202    7.1                                             ______________________________________                                    

EXAMPLE 5

The X-ray powder diagram after the first dehydrogenation and one furthercycle of hydrogenation/dehydrogenation and after annealing at 600° C.shows sharp reflections different from those of the hexagonal compoundMg₅ Pd₂ (Co₂ Al₅ type) [L. Westin, Acta Chem. Scand. 22 (1968) 2574]which reflections may be assigned to the so far unknown intermetallicphase Mg₂ Pd having a hexagonal lattice structure (a-6.980 Å; c-12.605Å) as follows:

    ______________________________________                                        d[A].sub.exp.                                                                           d.sub.calc.   hxl    I.sub.exp.                                     ______________________________________                                        3.4839    3.4898        110    19.9                                           3.1649    3.1515        004    44.1                                           2.3203    2.3257        015    45.3                                           2.2361    2.2481        121    100.0                                          2.1301    2.1480        122    11.9                                           2.0092    2.0145        030    11.0                                           1.8430    1.8493        124    4.2                                            1.8253    1.8166        033    16.1                                           1.5810    1.5743        008    12.3                                           1.5687    1.5733        035    7.6                                            1.4135    1.4218        043    12.3                                           1.3149    1.3191        140    10.2                                           1.2906    1.2959        045    27.1                                           1.2103    1.2147        235    7.2                                            1.1172    1.1168        146    6.4                                            ______________________________________                                    

The crystalline Mg₂ Pd reversibly reacts with H₂ under pressure to formthe so far unknown crystalline ternary hydride Mg₂ PdH₂ (decompositiontemperature at normal pressure 250°-255° C.) which is characterized byX-ray powder analysis.

EXAMPLE 10

The amorphous hydride MgZn₂ H₂ upon heating at 300° C. yields the knowncrystalline intermetallic compound MgZn₂ [T. Ohba et al., ActaCrystallogr. Sect. C: Cryst. Struct. Commun. (1984) C 40, 1) identifiedby X-ray powder analysis.

EXAMPLE 11 TO 22

Examples 11 to 22 were carried out and worked up in the same manner asin Example 1. The experimental data are set forth in Tables 2 and 2a.

                                      TABLE 2                                     __________________________________________________________________________    Reactions to metal hydrides M.sup.1 H.sub.n with bis(allyl)metal              compounds (M.sup.2 A.sub.2)                                                   at room temperature to give intermetallic compounds or ternary hydrides.      Ex-              Sol-  React.-          Composition [%].sup.b)                ample                                                                             M.sup.1 H.sub.n                                                                      M.sup.2 A.sub.2                                                                     vent  Time   Propene.sup.a)                                                                      Solid                                                                             M.sup.1 M.sup.2 H                                                                         Yield.sup.c)              No. g (mmol)                                                                             g (mmol)                                                                            [ml]  [h]    [%]   [g] Empirical Formula                                                                         [%] RP.sup.d)             __________________________________________________________________________    11  CaH.sub.2 .sup.e)                                                                    PdA.sub.2                                                                           THF   18d.sup.f)                                                                           64 (0.3)                                                                            2.47                                                                              38.2 52.3 2.49 7.1                                                                        100 amorphous                 1.08 (24.4)                                                                          2.26 (12.0)                                                                         (40)                   Ca.sub.1.94 Pd.sub.1.00 H.sub.5.03                                             C.sub.1.20                           12  BaH.sub.2 .sup.g)                                                                    NiA.sub.2                                                                           THF   24     65 (4)                                                                              5.44                                                                              74.7 16.0 1.6 6.7                                                                         99  amorphous                 4.43 (29.9)                                                                          2.11 (15.0)                                                                         (37)                   Ba.sub.2.00 Ni.sub.1.00 H.sub.5.87                                             C.sub.2.05     (BaH.sub.2)           13  BaH.sub.2 .sup.g)                                                                    NiA.sub.2                                                                           THF   24     65 (3)                                                                              2.90                                                                              64.2 26.5 2.1 6.7                                                                         92  amorphous                 2.11 (14.3)                                                                          2.03 (14.3)                                                                         (37)                   Ba.sub.1.04 Ni.sub.1.00 H.sub.5.64                                             C.sub.1.09                           14  LiH.sup.h)                                                                           NiA.sub.2                                                                           THF   20     69 (2)                                                                              1.06                                                                              16.0 63.5   83  amorphous                 0.26 (23.6)                                                                          (13.9)                                                                              (50)                   Li.sub.2.10 Ni.sub.1.00               15  LiH.sup.h)                                                                           NiA.sub.2                                                                           Toluene                                                                             216    63 (2)                                                                              2.36                                                                              8.4 68.4 1.93 17.1                                                                        100 amorphous                 0.25 (23.3)                                                                          (27.4)                                                                              (44)                   Li.sub.1.04 Ni.sub.1.00 H.sub.1.64                                             C.sub.1.22                           16  LiH.sup.h)                                                                           PdA.sub.2                                                                           THF   60     51    1.58                                                                              8.5 83.7 1.91 3.4                                                                         88  Pd                        0.29 (28.3)                                                                          2.68 (14.2)                                                                         (50)                   Li.sub.1.55 Pd.sub.1.00 H.sub.2.41                                             C.sub.0.36                           17  LiH.sup.h)                                                                           PtA.sub.2                                                                           THF   24     60 (1)                                                                              2.14                                          0.21 (20.3)                                                                          2.85 (10.3)                                                                         (50)                                                         18  B.sub.2 H.sub.6                                                                      NiA.sub.2                                                                           Toluene                                                                             24     -- (25)                                                                             2.05                                                                              21.9 63.4 2.9 10.6                                                                        77  amorphous.sup.i)          0.88 (31.7)                                                                          4.04 (26.7)                                                                         (140)                  B.sub.1.88 Ni.sub.1.00 H.sub.2.69                                             C.sub.0.82                            19  B.sub.2 H.sub.6                                                                      NiA.sub.2                                                                           Toluene                                                                             60     18 (26)                                                                             2.56                                                                              13.0 69.2 2.7 14.8                                                                        73  amorphous.sup.j)          0.54 (19.6)                                                                          5.84 (41.5)                                                                         (90)                   B.sub.1.02 Ni.sub.1.00 H.sub.2.29                                             C.sub.1.05                            20  B.sub.2 H.sub.6                                                                      PdA.sub.2                                                                           THF   0.7(-15° C.)                                                                  72    1.04                                                                              16.3 80.0 0.73 1.7                                                                        73                            0.39 (14.3)                                                                          2.23 (11.9)                                                                         (50)  20(-30° C.)                                                                             B.sub.2.00 Pd.sub.1.00 H.sub.0.96                                             C.sub.0.19                            21  SiH.sub.4                                                                            NiA.sub.2                                                                           Toluene                                                                             0.5(0° C.)                                                                    14 (35)                                                                             2.76                                                                              24.7 45.6 4.3 21.7                                                                            amorphous                 1.10 (34.2)                                                                          4.22 (30.0)                                                                         (150) 72(RT)           Si.sub.1.13 Ni.sub.1.00 H.sub.5.54                                             C.sub.2.23                           22  SiH.sub.4                                                                            PdA.sub.2                                                                           THF   16(-30° C.)                                                                   79 (16)                                                                             1.68            81  amorphous                 (14.6) 2.75 (14.6)                                                                         (50)                                                         __________________________________________________________________________     .sup.a) The figures in brackets denote % of propane.                          .sup.b) By elementary analysis.                                               .sup.c) Based on initially employed M.sup.2.                                  .sup.d) X-ray powder analysis of the solid prior to dehydrogenation or        thermal treatment, respectively.                                              .sup.e) CaH.sub.2 technical grade, 95%.                                       .sup.f) PdA.sub.2 still present in solution after 8 d.                        .sup.g) BaH.sub.2 94%.                                                        .sup.h) Catalytically prepared lithium hydride, % [U.S. Pat. No.              4,396,589].                                                                   .sup.i) Specific surface area 150 m.sup.2 /g.                                 .sup. j) Specific surface area 164 m.sup.2 /g.                           

                                      TABLE 2a                                    __________________________________________________________________________    Dehydrogenation of the ternary metal hydrides and thermal treatment of        the intermetallic compounds,                                                  respectively, of Examples 11 to 22 and results of X-ray powder analyses.      Ex- 1st Dehydr. or Therm. Treatm..sup.a)                                                                      2nd Dehydr. or Therm. Treatm..sup.a,e)                                                         Composition [%].sup.f)       ample                                                                             ml of Gas.sup.b) Comp. of Gases [%].sup.c)                                                                ml of Gas.sup.b) Comp. of Gases                                               [%].sup.c)       M.sup.1 M.sup.2 H C          No. Amount [g]                                                                          H.sub.2                                                                         CH.sub.4                                                                         C.sub.2 H.sub.6                                                                  C.sub.3 H.sub.8                                                                  C.sub.4 H.sub.10                                                                 .sup.d) Amount [g]                                                                           H.sub.2                                                                            CH.sub.4                                                                           Empirical                                                                                RP.sup.g)         __________________________________________________________________________    11  43     6                                                                              88 37 2  -- h)      44.sup.i)                                                                            92    8   40.1 52.4 2.06                                                                           j)0                                                                Ca.sub.2.00 Pd.sub.1.00                                                       H.sub.4.15 C.sub.0.85        12  45    39                                                                              54 -- 4  3  BaH.sub.2                                             13  60    25                                                                              71 -- 4  0.4                                                                              k)                                                    14  110   80                                                                              13 -- 3  1          16     86   14   15.3 70.7 1.38                                                                           Ni3                                                                Li.sub.1.83 Ni.sub.1.00                                                       H.sub.1.14 C.sub.0.37        15  85                          38     53   45              Ni                16  55    64                                                                              24 -- 6  --         72     92   --              l)                17  48    39                                                                              22 -- 6  3          65     100       6.1 88.4 1.16 0.57                                                            Li.sub.1.92 Pt.sub.1.00                                                       H.sub.2.54 C.sub.0.10        18  149   11                                                                              67 5  15 2  amorphous                                                                     (C 2.2, H 0.0%)                                       19  121   14                                                                              60 7  18 1  amorphous                                                                     (C 7.1, H 1.3%)                                       20   0                  amorphous                                             21  140    2                                                                              46 5  47 -- amorphous                                                                     (C 2.5, H 0.6%)                                       22  27     8                                                                              34 8  42 31 amorphous.sup.m)                                      __________________________________________________________________________     .sup.a) A sample of 1 to 2 g of the solid is heated in the                    thermovolumetric apparatus [B. Bogdanovic, B. Spliethoff, Chem. Ing.          Techn. 55 (1983) 156] from room temperature to 400° C. at a heatin     rate of 1° C./min.                                                     .sup.b) 20° C., 1 bar.                                                 .sup.c) According to massspectrometrical analysis.                            .sup.d) Result of Xray powder analysis after the 1st dehydrogenation or       thermal treatment, respectively.                                              .sup.e) After the sample had been hydrogenated in an autoclave at 15 bar      and 210° C. for 24 h.                                                  .sup.f) After the 2nd dehydrogenation or thermal treatment, respectively,     according to elementary analysis.                                             .sup.g) Result of Xray powder analysis after the 2nd dehydrogenation or       thermal treatment, respectively.                                              .sup.h) The sample shows minor crystalline portions.                          .sup.i) In this case hydrogenation at 20° C., 13 bar, 24 h; the        sample may be reversibly hydrogenated at 138° C. and dehydrogenate     at 148° C.                                                             .sup.j) Low crystallinity; reflections at d(intensity %) 2.2480(100),         2.4099(40), 1.4953(40), 2.8126(36), 2.0095(36).                               .sup.k) Very broad reflections, attributable to BaH.sub.2 and Ni; C 1.2,      0.8%.                                                                         .sup.l) Reflections at d(intensity %) 2,280(100), 1.985(20), 2.776(27),       3.809(18), 3.887(17).                                                         .sup.m) The sample cannot be hydrogenated under standard conditions.          Elementary analysis: Si 17.0, Pd 79.0, H 0.32, C 3.63%; empirical formula     Si.sub.1.00 Pd.sub.1.22 H.sub.0.51 C.sub.0.50.                           

EXAMPLE 16

The amorphous intermetallic compound Li₁.5 Pd, after heating at 400° C.and one cycle of hydrogenation/dehydrogenation shows broad reflectionsin the X-ray diagram (cf. Table 2a). LiPd in a crystalline form has beenknown (cubic crystal lattice, CeCl type) [J. H. N. Van Vucht, K. H. J.Buschow, J. Less-Common Metals 48, (1976) 345; O. Loebich, Ch. J. Raub,J. Less-Common Metals 55 (1977) 67].

EXAMPLE 17

The amorphous intermetallic compound Li₂ Pt under standard conditionsreversibly reacts with hydrogen (Table 2a). The crystalline Laves phaseLi₂ Pt has been known [W. Bronger et al., J. Less-Common Metals 43,(1975) 143; O. Loebich, Ch. J. Raub, J. Less-Common Metals 70 (1980)47].

EXAMPLE 23

To a solution of 2.19 g (26.6 mmol) of Mg(C₂ H₅)₂ in 40 ml of THF thereis dropwise added at room temperature with stirring within 1 h asolution of 2.56 g (13.6 mmol) of Pd(η-C₃ H₅)₂ in 20 ml of THF. Alreadyupon the addition of the first drops a black precipitate was formed andgas evolution began. The gas evolved during the reaction (4 h) wascollected in a gas burette connected to the reaction vessel. Accordingto analysis by mass spectrometry, 29.9% of C₂ H₄, 17.4% of C₂ H₆ and12.9% of C₃ H₆, each relative to the calculated amounts, were released.

The batch was stirred at room temperature for another 22 h. Then thevolatiles were evaporated at 0.27 mbar (0.2 mmHg) and condensed in twocold traps arranged in series (-78° C. and -196° C.). The gasescondensed in the trap cooled at -196° C. were evaporated, collected in agas burette and analyzed by mass spectroscopy; there were detected 12.2%of C₂ H₄, 4.8% of C₂ H₆ and 36.8% of C₃ H₆, each relative to thecalculated amounts. The distillation residue was stirred with 40 ml offresh THF, the solid was separated from the solution by filtration,washed with THF until colorless and then dried under high vacuum.

There were obtained 1.92 g of a black, highly pyrophoric solid havingthe composition Mg 18.8, Pd 78.2, H 0.68, C 2.5, conforming to anempirical formula of MgPdH₀.92 C₀.29 (98% based on Pd). According to theX-ray powder analysis, the solid was amorphous.

In the thermal treatment (up to 400° C., 1° C./min), 1.05 g of the solidproduced 25 ml of gas (20° C., 1 bar) having the composition: H₂ 15.2,CH₄ 9.1, C₃ H₈ 96.4, C₄ H₁₀ 36.4%. After a pressure hydrogenation (25bar of H₂, 250° C., 24 h), the sample of the solid was again subjectedto the programmed temperature-controlled thermolysis as above; noevolution of gas occurred, and the sample due to its X-ray powderdiagram was amorphous. The mother liquor obtained upon the recovery ofthe solid upon hydrolysis gave 24.7% of C₂ H₆ and 30.5% of C₃ H₆,relative to the respective calculated amounts, and the aqueous phasecontained 12.5 mmol or Mg²⁺ (45% of the starting amount) and 0.34 mmolof Pd²⁺ (2.5% of the calculated amount). Due to the gases evolved in thereaction and upon hydrolysis and to the analysis of the solid and of thesolution, the reaction of Mg(C₂ H₅)₂ with Pd(η-C₃ H₅)₂ may be describedby the reaction equation (4) as set forth hereinabove.

APPLICATION EXAMPLE 1 [Use of the amorphous intermetallic hydride Mg₂PdH₂ (Example 5) as a catalyst for the selective hydrogenation ofhexyne-3 to form cis-hexane-3].

0.25 g (7.6 mmol) of the active magnesium hydride prepared according tothe European Patent No. 0 003 564 Cr cat., 20° C.) in 5 ml of toluenewere admixed with a solution of 0.53 mg (0.003 mmol) of Pd(η³ -C₃ H₅)₂in 4 ml of toluene, and the suspension was stirred for 0.5 h. After 20 hof stirring under a hydrogen atmosphere (1 bar of hydrogen, 20° C.) 3.8ml (34 mmol) of hexyne-3 were added (molar ratio ofPd:hexyne-3-1:23000), whereupon an immediate hydrogen consumption beganto occur. Until completion of the reaction 790 ml of H₂ (1 bar, 20° C.)were taken up (99% of the theoretical amount) in the course of 1 h 40min.

According to the gas-chromatographic analysis the product had thefollowing composition: cis-hexane-3 96%, trans-hexane-3 2%,trans-hexane-2 0.4%, cis hexane-2 0.4%, n-hexane 1%.

APPLICATION EXAMPLES 2 TO 8 [Use of the amorphous intermetallic nickelcompounds as hydrogenation catalysts]

The amorphous intermetallic nickel compounds Mg₂ NiH₂ (Example 1),NiBC_(x) H_(y) (Example 19), NiB₂ C_(x) H_(y) (Example 16), NiSiC_(x)H_(y) (Example 21), MgNiC_(x) (Example 3), BaNi (Example 13) and thecrystalline compound Mg₂ NiH₄ (after 34 cycles ofhydrogenation/dehydrogenation, Example 1), were used as hydrogenationcatalysts for the hydrogenation of a mixture of cyclohexane andheptane-1 in a molar ratio of 10:7 (molar ratio Ni:alkene-1:40) andcompared to a conventional Raney nickel catalyst.

In FIG. 1, the respective hydrogen consumption rates are plotted overthe period of reaction.

Mg₂ NiH₂ has proven to be the best hydrogenation catalyst having anactivity of about 12 times that of Raney Ni. Both NiB₂ C_(x) H_(y) andNiBC_(x) H_(y) are still 6 times as active as Raney Ni is undercomparable conditions. Particularly conspicuous are the very largesurface areas of 149.9 m² /g and 164.0 m² /g, respectively, of the boroncompounds which are supposed to contribute to the high activities of thecatalysts.

The activity of NiSiC_(x) H_(y) is nearly identical to that of NiBC_(x)H_(y). Even the BaNi, in spite of its low surface area, showsconsiderable activity exceeding that of Raney Ni by a factor of 1.4.

It will be understood that the specification and examples areillustrative but not limitative of the present invention and that otherembodiments within the spirit and scope of the invention will suggestthemselves to those skilled in the art.

What is claimed is:
 1. An intermetallic compound selected from the groupconsisting ofa) crystalline Mg₂ Pd, b) amorphous MgPd, c) Mg₂ Pt, d)MgPt, e) Li₂ Ni f) LiNi, g) BaNi, h) Ba₂ Ni, i) amorphous LiPd, j)amorphous Li₂ Pt, k) Ca₂ Pd, and
 2. A compound according to claim 1,wherein such compound is crystalline Mg₂ Pd.
 3. A compound according toclaim 1, wherein such compound is amorphous MgPd.
 4. A compoundaccording to claim 1, wherein such compound is Mg₂ Pt.
 5. A compoundaccording to claim 1, wherein such compound is MgPt.
 6. A compoundaccording to claim 1, wherein such compound is Li₂ Ni.
 7. A compoundaccording to claim 1, wherein such compound is LiNi.
 8. A compoundaccording to claim 1, wherein such compound is BaNi.
 9. A compoundaccording to claim 1, wherein such compound is Ba₂ Ni.
 10. A compoundaccording to claim 1, wherein such compound is amorphous LiPd.
 11. Acompound according to claim 1, wherein such compound is amorphous Li₂Pt.
 12. A compound according to claim 1, wherein such compound is Ca₂Pd.